Methods for evaluating sensitivity (E), specificity (77) and predictive values (p's) for a laboratory technique are proposed for detection of a particular disease D. The methods for comparing sensitivities, specificities and their predictive values for two diagnostic procedures say ti, and t2 for a specific disease D are discussed. It is assumed that a definite result can be obtained on the presence or absence of disease D in each of a series of n patients together with their diagnoses by the two procedures. In this paper. Chi-square (7,2) tests are discussed for homogeneity of r and p's. In the end, two examples are illustrated to give practical concept. for using these methods.